Drawbench apparatus



Aug. 16, 1966 J. s. MILLER DRAWBENCH APPARATUS 5 Sheets-Sheet 1 FiledJune 25, 1963 Aug. 16, 1966 J. s. MILLER DRAWBENCH APPARATUS 5Sheets-Sheet 2 Filed June 25, 1965 INVENTOR.

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Aug. 16, 1966 Filed June 25, 1963 Aug- 16, 1966 J. s. MILLER 3,266,283

DRAWBENCH APPARATUS Filed June 25, 1963 5 Sheets-Sheet 5 INVENTOR.

JoHN SWMLLER BY United States Patent O 3,266,283 DRAWBENCH APPARATUSJohn S. Miller, Poland, Ohio, assignor to The McKay Machine Company,Youngstown, Ghia Filed June 25, 1963, Ser. No. 290,454 9 Claims. (Cl.72-284) The present invention relates to a drawbench, more particularlyto a drawbrench of the hydraulic type and to sub-assemblies particularlyadapted for use therewith, and the principal object of the invention newand improved devices of the character described.

As generally known in the trade, a drawbench is a device for drawingelongated stock, such as a rod, through a die in order to effect atransverse reduction in the size of the stock. In many cases, a powerfulhydraulic cylinder is employed to pull the stock through the die.

Since the stock to be drawn is initially of considerable length; sincesuch length is materially increased as a result of the drawingoperation; and since a hydraulic cylinder having a stroke at least aslong as the stock after drawing must be employed, the normallyconstructed drawbench tends to require a considerable length of floorspace. For example, and as will later appear, a conventional drawbenchfor drawing 20 foot stock to a length of 25 feet will require more than70 feet of oor space. In contrast, by the use of the present invention,a saving of about 20 feet of oor space length can be electuated with nodecrease in stock capacity.

Additionally, since the present invention utilizes the greater forceapplication effectiveness of a hydraulic cylinder on its out-strokerather than on its in-stroke as is conventional, a smaller diameterhydraulic cylinder and/or less hydraulic pressure and volume may beemployed with considerable cost savings. These and other advantages willreadily become apparent from a study of the following description andform the drawings appended hereto.

In the drawings accompanying this specification and forming a part ofthis application there is shown, for purpose of illustration, anembodiment which the invention may assume, and in these drawings:

FIGURE l is a side elevational View of a preferred embodiment of theinvention,

FIGURE 2 is a top plan view thereof,

FIGURE 3 is an enlarged plan View, partially in section, and generallycorresponding to the line 3 3 of FIGURE l,

FIGURE 4 is an enlarged plan view, partially in section, and generallycorresponding to the line 4 4 of FIGURE 1,

FIGURE 5 is a still further enlarged, fragmentary sectional viewgenerally corresponding to the line 5 5 of FIGURE 2,

FIGURE 6 is a sectional View generally corresponding to the line 6 6 ofFIGURE 4,

FIGURE 7 is a reduced size, generally diagrammatic view similar toFIGURE l, and

FIGURE 8 is a view similar to FIGURE 7 and to the same scale but ofprior art apparatus.

With reference to FIGURES 1 and 2 and for convenience of disclosure, theapparatus herein illustrated may conveniently be divided into a diestation A, a stock entry portion B to the left of the die station, and astock drawing portion C to the right of the die station. Associated withthe stock entry portion B is a stock entry table 10 and interposedbetween the latter and the die station A is a stock entry carriage 11having a relatively short path of travel toward and away from the diestation. To the right of the die station, the stock drawing portion Cprovides a draw carriage 12 shown adjacent the die station but shiftablefrom such position to the extreme right-hand end of the apparatus. Aswill later be disclosed in greater detail, each carriage 11, 12 isprovided with jaws for gripping the stock to be drawn through the diestation A.

In brief, operation of the apparatus thus far described will be asfollows: The stock to be drawn will be placed on the stock entry table10 with its right-hand end adjacent the die station. The stock entrycarriage will next grip the stock and will then Ibe shifted to the rightto force the stock end through the die station far enough to permit itto be gripped by the stock drawing carriage 12. After the stock drawingcarriage 12 has gripped the stock, such carriage will -be shifted -tothe right to draw the remainder of the stock through the die stationthus completing the drawing operation. With the drawing operationcompleted, the stock will be released by the carriage 12 for removalthereof from the apparatus. Both carriages may now be returned to thepositions shown in FIGURES l and 2 and the foregoing operations repeatedon another piece of stock.

Still referring to FIGURES 1 and 2, the means for effecting movement ofcarriage 12 to the right comprises a pair of elongated uid cylinderassemblies 13 in spacedapart, side-.by-side relation. As will later bedisclosed in greater detail, the right-hand end of each cylinderassembly is secured to respective upright ears 14 of a frame structure15 whose other end provides upright ears 16 forming a part of the diestation A. The left end of each cylinder assembly 13 is supported on astanchion 17, similar stanchions 18 being interposed between stanchions17 and the frame 15 and spaced along the cylinder assemblies to supportthe latter. Stanchions 18 may also conveniently be employed to supportthe stock entry table 10.

Turning now to FIGURE 5 wherein the left-hand end of one of the cylinderassemblies 13 is illustrated, it is to be understood that both cylinderassemblies are preferably identical and thus only one need be shown anddescribed in detail. As presently disclosed, cylinder assembly 13comprises an elongated cylinder barrel 19 whose right-hand end isanchored to a frame ear 14 by means later to appear. The left-hand endof the barrel 19 is suitably closed by an end plug 20 to which isconnected a conduit 21 through which fluid may pass into and out of thecylinder barrel.

Slidable in the cylinder barrel is a piston 22 carrying suitable sealingrings 23 and secured to the right-hand end of piston 22 is a tubularpiston rod 24. In the present embodiment, a stud `25 has an enlarged end26 suitably anchored to the piston rod 24 and a shank portion 27extending through an enlarged central aperture 28 in the piston. Suchaperture is reduced in size at the left of the piston and an O sealingring 29 prevents the escape of fluid between the piston and the stud.The eXtreme left-hand end of stud 25 is threaded to receive a pair ofnuts 30 which retain the piston assembled on the stud.

It is an important feature of the present invention that the ends ofpiston 22 are spherical and are seated against respectivecomplementarily formed washers 31, 32 assembled over the stud shank.This arrangement permits the piston rod 24 to deflect transverselywithout exerting a force on the piston tending to cock it in itscylinder bore. Obviously, because of the great length of the piston rod,it will have a tendency to deflect, even of its own weight, a small butsignificant amount.

Since piston rod 24 is subjected to compressive forces, rather thantension forces, during the stock drawing operation, it is important thatthe piston rod be of maximum size to resist any tendency to buckle.Accordingly, the piston rod is herein shown to have a transverse sizebut slightly smaller than the bore of the cylinder barrel 19. With sucha piston rod to cylinder bore relationship and With such a long pistonrod, transverse deflection of th rod could causeV it to rub along andscratch the cylinder barrel. To eliminate this possibility, the pistonrod is presently covered with sleeves 33 of non-ferrous, relatively softImaterial in end-to-end, a-butting relation. Such sleeves may be formedof a suitable lplastic or a soft metal such as babbit. Although notshown, a slight operating clearance will be provided between theexterior of the sleeves 33 and the lbore of the cylinder barrel 19.

Referring now to FIGURE 3, the right-hand end of .the cylinderrbarrel 19is externally threaded to receive a shouldered sleeve 34 and the latteris tightly clamped against the frame ear 14 by means of a nut 35threaded on the sleeve. Seated against the right-hand end of sleeve 34and concentric with the cylinder barrel 19 is a hollow piston rod 36through which the piston rod 24 passes. Here again, operating clearanceover the piston rod sleeves 33 will be provided. Hollow piston rod 36 isVrrnly clamped against the sleeve 34 by means of a split collar 37bolted to the frame ear 14 and having a radially inwardly projectingflange seated in an annular groove formed in the rod 36.

, Y For a purpose later to appear, the end of hollow piston duced indiameter and passes through a close-fitting aperture in a frame ear 16and is externally threaded to receive a nut 41 which clamps the rodfirmly in position.

`Enclosing the right-hand end of hollow piston rod 36 is an axiallyelongated collar 42 bolted to the ear 16. The interior of collar 42carries an annular wiper member 43,

' similar to 38, and provides an annular recess 44, similar to recess39. A drain conduit 45 carries fluid away from recess 44 and returns itto the pressure source connected to the previously described conduit 40.

Turning next to FIGURE 4, it will be noted that the piston rod 24extends beyond the die station A and is secured to the draw carriage 12by any suitable means, such as, for example, the flat-head capscrews 46.Carriage 12, therefore, spans the piston rods 24 of the two cylinderassemblies 13 (see FIGURE 6) and ties them together for unitarymovement.

In order to guide the piston rods 24 as they are shifted to the rightfrom the position seen in FIGURES 3 and 4, each is contained within anelongated, tubular member 47 which provides a small radial operatingclearance over such piston rod. Such members 47 serve a multiple purposein that they not only function to guide the rods, but also support themagainst buckling and protect them from dirt and the like. As best seenin FIGURE 4 wherein one of the members 47 is shown in section, eachmember is secured to a respective collar 42 by means of a suitablecollar 48 and each extends therefrom the full length of the apparatusdrawing portion C and has its free end supported by an overhangingstanchion 49 (FIGURES l, 2 and 6). Additional, identical stanchions S0are interposed between the stanchion 49 and the frame 15 and are spacedalong the members 47 Vfor adequate support thereof. As best seen inFIGURE 6 and since the carriage 12 extends between the ends of thepiston rods 24, the facing sides of the tubular members 47 are cut awayto pass the carriage. At each of the stanchions 50, 49, a conduit 51provides for the return of oil in a manner similar to the conduits V45previously described.

- barrel 53 having the usual seal structure at each end for sealingaboutl respective, adjoining piston rod portions. Conduits 54, 55provide for passage of fluid to the interior of the bore of cylinderbarrel 53 on opposite sides of the piston 52. From the foregoing it willnow be clear that the piston rod 36, piston 52 and cylinder barrel 53con-V stitute a cylinder assembly which is Vreversed from the ordinaryassembly in that the piston and its rod are held stationary while thecylinder barrel is shiftable axially of the piston rod. The cylinderbarrel 53 and all the other associated parts hereinabove described are,of course, duplicated on the opposite side of the apparatus.

The previously mentioned stock entry carriage 11 Vis herein shownintegral with the cylinder barrels 53 and is provided with opposed jaws56 for gripping the stock S shown in phantom lines. Although not shown,a suitable actuating mechanism may be employed to effect jaw movement togrip'and release the stock. Similarly, and with reference toFIGURE 4,the stock drawing carriage 12 will be provided with opposed jaws 57 forgripping the stock. Here again, suitable means may be provided foreffecting jaw movement to grip and release the stock.

Completing the structure and referring to FIGURES 3 and 4, a die 58 willbe suitably mounted at the die station A. For example, the die may carryopposed lugs 59 which fit closely within respective slots formed in theframe ears 16.

With the parts positioned as illustrated inFIGURES l through 5 and withthe carriage jaws 56, 56 and 57, 57 separated, a piece of stock S willbe pushed between the jaws 56 of thestock entry carriage 11 and intoabutment with the die 58. laws l56 will now be actuated to clamp thestock and fluid under pressure admitted through the conduits 55 to causethe cylinder barrels 53 and the asso-Y ciated carriage 11 to move towardthe die 58. MovementV of carriage 11 as above described will force theend of the stock through the die 58 far enough so that the Vstock can begripped by the carriage jaws 57 as illustrated in FIGURE 4. Jaws 57 willnext be actuated to grip the stock while the jaws 56 will be releasedtherefrom. Carriage 11 may, if desired, be returned at this time to theI Vpressure will be admitted through conduits 21 to thus shift thepistons 22, the piston rods 24 and the carriage 12 to the right.Movement of the carriage 12 in this direction will draw the stockthrough the die 58 as will be understood. When the entire length ofstock has been drawn through the die 58, jaws 57 will be shifted torelease the stock whereupon the latter can drop free of the apparatus.

During the foregoing operational sequence, oil under pressure will becontinuously supplied through the conduits 40 to each of the recesses39. Such oil will then flow along the exterior of each piston rod 24 tolubricate the latter as they move to the right. The majority of such oilwill be recovered by the recesses 44 and the conduits 45; however, anyexcess oil drawn along with the piston rods will be returned to itssource through the conduits 55 at respective stanchions 50, 49.

Following the drawing operation hereinabove described, the carriage 12will be at the extreme light-hand end of the apparatus and, since thecylinder assemblies 13 which effect its movement are single acting,separate means (not shown) will be employed to return this carriage tothe position seen in FIGURE 4. This may readily be accomplished by, forexample, a fluid cylinder having cable connection with the carriage orby an electric motor having driving connection with a chain which is inturn connected to the carriage. Various other expedients may as well beused, it being understood that relatively little force will be requiredto so return the carriage.

Regardless of the means used to return the carriage, it

will be understood that such operation causes the pistonv rods 24 tomove to the left, the wipers 43, 38 wiping the rods free of any foreignmatter and the continuous oil owiiushing the rods and carrying away anysuch foreign matter. Accordingly, as the piston rods are retracted intotheir cylinder barrels 19, they will be cleansed so as not to drawforeign matter into the barrels. With the carriage 12 positioned onceagain as seen in FIGURE 4, another stock drawing cycle may be commenced.

As earlier mentioned, a major advantage of the present drawbench overthose heretofore known is a considerable reduction in spacerequirements. This is accomplished by the hereinabove discloseddisposition of the draw carriage cylinder assemblies on the entry sideof the die stand, or station, in superposed relation with the entrytable, rather than on the exit side of the die stand.

FIGURE 7 illustrates the present invention wherein there is shown adrawbench for receiving foot lengths of stock and for drawing such stockto a length of feet. In order to draw the stock to a length of 25 feet,carriage travel of 25 feet will be required (ignoring, for presentpurposes, a certain amount of carriage overtravel which must normally beprovided). With an assumed carriage travel of 25 feet, each carriageshifting cylinder must have a travel of 25 feet. Note in FIGURE 7 thatthe 25 foot stroke carriage actuating cylinder is disposed on the entryside of the die stand in superposed relation with the 20 foot entrytable. Thus, the apparatus requires a total of 55 feet of floor space ifthe die stand is assumed to require 5 feet of space.

In contrast and referring to FIGURE 8, prior-art apparatus of the samecapacity requires the same 20 foot entry table, the same 5 foot diestand, the same 25 foot carriage travel, and the same 25 foot stroke,carriage actuating cylinder. However, since the prior-art, carriageactuating cylinder is disposed on the exit side of the die stand, atotal of 75 feet of oor space is required. Clearly, this is 20 feet morefloor space than is required by the presently disclosed, novelapparatus.

In view of the foregoing it will be apparent to those skilled in the artthat I have accomplished at least the principal object of my inventionand it will also be apparent to those skilled in the art that theembodiment herein described may be various changed and modified, withoutdeparting from the spirit of the invention, and that the invention iscapable of uses and has advantages not herein specifically described;hence it will be appreciated that the herein disclosed embodiment isillustrative only, and that my invention is not limited thereto.

I claim:

1. A drawbench comprising a fixed die station having a stock entry sideand a stock exit side, first and second carriages on the entry and exitdie station sides respectively and each having means for gripping thestock, `and a pair of concentric, fiuid cylinder assemblies forrespectively urging said first carriage toward said die station to pushone end of a length of gripped stock therethrough and for urging saidsecond carriage away from said die station to pull the remainder of thelengthof gripped stock therethrough.

2. The construction of claim 1 wherein each fluid cylinder Vassemblycomprises a cylinder barrel, a piston within each cylinder barrel and apiston rod connected to each piston, and wherein the cylinder barrel ofeach assembly is disposed on the entry side of said die station.

3. The construction of claim 2 wherein the piston rod of one assemblyand the cylinder barrel of the other assembly are fixed against axialmovement, and wherein the cylinder barrel of said one assembly and thepiston rod of the other assembly are connected to said first and secondcarriages respectively for effecting movement thereof.

4. The construction of claim 3 wherein the piston rod of said oneassembly is hollow and wherein the piston rod of said other assemblyextends therethrough for connection to said second carriage.

5. The construction of claim 4 wherein a tubular member is in axialalignment with the piston rod of said other cylinder assembly forreceiving Vand supporting such rod against lateral deflection when thelatter is projected outwardly of its cylinder barrel, and wherein thepiston rod of said one cylinder assembly is interposed between saidmember and the cylinder `barrel of said other assembly.

6. A drawbench comprising a fixed die station having a stock entry sideand a stock exit side, first and second carriages on the entry and exitdie station sides respectively and each having means for gripping thestock, two hydraulic cylinder assemblies in side-by-side relation onopposite sides of the path of stock travel through said die station forurging said first carriage toward said die station to push one end of alength of gripped stock therethrough and for urging said second carriageaway from said die station to pull the remainder of the length ofgripped stock therethrough, each cylinder assembly providing a pair ofconcentric cylinder barrels disposed on the entry side of said diestation, a piston within each barrel and a piston rod connected to eachpiston, one of the piston rods and one of the cylinder barrels of eachassembly being fixed against axial movement and the other piston rod andthe other cylinder barrel of each assembly being respectively connectedto said second and first carriages for effecting movement thereof, and apair of tubular members in axial alignment with respective, said otherpiston rods for receiving and supporting such rods against lateraldeflection during movement of said second carriage away from said diestation.

7. A drawbench, comprising a fixed die station having a stock entry sideand a stock exit side, a draw carriage on the exit side of said diestation and having means for gripping the stock, `a hydraulic cylinderassembly including a cylinder barrel on the stock entry side of said diestation and a piston rod extending from one end of said barrel anddirectly connected to said carriage for moving the latter away from saiddie station to draw the stock therethrough, said piston rod beingstressed in compression during such carriage movement and being slightlysmaller in transverse section than the bore of said cylinder barrel andlow friction, non-marring material covering said piston rod to insureagainst scratching of said bore by said rod, a tubular member whichpartially er1- closes said rod and which supports the same againstlateral deflection when it is projected outwardly of said cylinderbarrel, and means at said one cylinder barrel end for bathing saidpiston rod and the interior of said tubular member to remove deleteriousmaterial from said piston rod prior to retraction thereof into saidcylinder barrel and to remove such deleterious material from saidtubular member.

8. A drawbench, comprising a die having a stock entry side and a stockexit side, a stock gripping jaw on the exit side of said die, means forpushing the forward end of the stock from said entry side through thedie opening and to project from said exit side, means for engaging saidgripping jaw on the projecting portion of said stock, and a fluidcylinder located on said entry side and having a piston rod connected tosaid stock gripping jaw for pushing the latter in a direction away fromsaid exit side and thereby draw the remainder of the stock through saiddie.

9. A drawbench, comprising a die having a stock entry side and a stockexit side, first and second stock gripping jaws located on said entryand exit sides respectively, means for engaging said first gripping jawson the stock inward of its forward end, a first fiuid cylinder formoving said first gripping jaws toward said die an amount to push theforward end of the stock from said entry side through the die openingand to project from said exit side, said first gripping jaws thereuponbeing released from said stock, means for engaging said second grippingjaws on the projecting forward end of said stock, and a second iiuidcylinder located on the entry side of said die and having a piston rodconnected to said seclond gripping jaws for pushing,7 the latter awayfrom said exit side and thereby draw the remainder of the stock throughsaid die.

References Cited by the Examiner UNITED STATES PATENTS Brotherhood92-179 McCool 72-284 Algen 72-284 Moltrup 72-284 Weatherhead 92-179 82,307,432 1/1943 Tuttle 205-5 2,339,959 1/ 1944 Stadlin 205-5 2,634,5874/1953 Ptak 92-110 2,910,049 10/ 1959 Calder 92-110 FOREIGN PATENTS82,636 9/1957 Great Britain.

10 CHARLES W. LANHAM, Primary Examiner.

H. D. HOINKES, Assistant Examiner.

1. A DRAWBENCH COMPRISING A FIXED DIE STATION HAVING A STOCK ENTRY SIDEAND A STOCK EXIT SIDE, FIRST AND SECOND CARRIAGES ON THE ENTRY AND EXITDIE STATION SIDES RESPECTIVELY AND EACH HAVING MEANS FOR GRIPPING THESTOCK, AND A PAIR OF CONCENTRIC, FLUID CYLINDER ASSEMBLIES FORRESPECTIVELY URGING SAID FIRST CARRIAGE TOWARD SAID DIE STATION TO PUSHONE END OF A LENGTH OF GRIPPED STOCK THERETHROUGH AND FOR URGING SAIDSECOND CARRIAGE AWAY FROM SAID DIE STATION TO PULL THE REMAINDER OF THELENGTH OF GRIPPED STOCK THERETHROUGH.